US 9,906,045 B2 · Assignee: Samsung Electronics Co., Ltd. · Inventors: Kim; Nam Yun et al.
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A method of synchronization control of a power transmitting unit (PTU) includes network-connecting a PTU to a PTU operating in a slave mode by setting an operation mode of the PTU to a master mode, and transmitting a signal to a power receiving unit (PRU) by controlling either one or both of a communication time and a communication frequency of the PTU operating in the slave mode.
1.
1 of 18 drawing sheets so far from the published document, cropped to the drawing. Every sheet is in the USPTO PDF.
What the patent claimed, word for word. All of it is now free to use.
This application claims the benefit under 35 USC 119(a) of Korean Patent Application No. 10-2013-0084218 filed on Jul. 17, 2013, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes.
1.
The following description relates to a method and an apparatus for synchronization control in a wireless power transmission system.
Wireless power transmission refers to energy transmitted to a power receiving unit (PRU) from a power transmitting unit (PTU) via magnetic resonant coupling. Accordingly, a wireless power transmission system or a wireless power charging system includes a source device for wirelessly transmitting power and a target device for wirelessly receiving power. The source device may be referred to as a source or the PTU. Also, the target device may be referred to as a target or the PRU.
The source device includes a source resonator, and the target device includes a target resonator. Magnetic resonant coupling occurs between the source resonator and the target resonator.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
In one general aspect, a method of synchronization control of a power transmitting unit (PTU) includes network-connecting a PTU to a PTU operating in a slave mode by setting an operation mode of the PTU to a master mode; and transmitting a signal to a power receiving unit (PRU) by controlling either one or both of a communication time and a communication frequency of the PTU operating in the slave mode.
The signal may include a beacon signal.
The transmitting of the signal to the PRU may include controlling a transmission start time of a signal sequence to be transmitted to the PRU.
The transmitting of the signal to the PRU may include controlling a transmission period of a signal sequence to be transmitted to the PRU.
The transmitting of the signal to the PRU may include transmitting a control signal to the PTU operating in the slave mode to enable the PRU to receive a single signal during a single time slot.
The transmitting of the signal to the PRU may include controlling either one or both of the communication time and the communication frequency based on information on a preset signal.
The transmitting of the signal to the PRU may include controlling either one or both of the communication time and the communication frequency of the PTU operating in the slave mode based on information on the transmitted signal.
The transmitting of the signal to the PRU may include controlling the communication frequency using frequency hopping.
The transmitting of the signal to the PRU may further include setting a frequency hopping sequence of the PTU and the PTU operating in the slave mode; and transmitting the signal to the PRU by controlling the communication frequency based on the frequency hopping sequence.
The transmitting of the signal to the PRU further may include controlling a hopping start frequency of the frequency hopping sequence.
The network-connecting of the PTU to the PTU operating in the slave mode may include setting an index of the PTU operating in the slave mode.
The setting of the index of the PTU operating in the slave mode may include transmitting information on the index to the PTU operating in the slave mode.
The PTU operating in the slave mode may be one of a plurality of PTUs operating in the slave mode; and the transmitting of the information on the index to the PTU operating in the slave mode may include generating the information on the index based on a sequential order in which the plurality of PTUs operating in the slave mode were network-connected to the PTU.
In another general aspect, a non-transitory computer-readable storage medium stores a program for controlling a computer to perform the method described above.
In another general aspect, a method of synchronization control of a power transmitting unit (PTU) includes network-connecting a PTU to a neighboring PTU operating in a master mode; comparing an index of the PTU to an index of a neighboring PTU operating in a slave mode in response to removal of the neighboring PTU operating in the master mode; and setting an operation mode of the PTU to the master mode in response to a result of the comparing being that the index of the PTU is higher than the index of the neighboring PTU operating in the slave mode.
The setting of the operation mode of the PTU to the master mode may include network-connecting the PTU to the neighboring PTU operating in the slave mode by setting the operation mode of the PTU to the master mode.
In another general aspect, a method of synchronization control of a power transmitting unit (PTU) includes network-connecting a PTU to a PTU operating in a slave mode by setting an operation mode of the PTU to a master mode; and synchronizing an operation of transmitting a signal from the PTU operating in the slave node to a power receiving unit (PRU) with an operation of transmitting a signal from the PTU to the PRU.
The synchronizing may include synchronizing the operation of transmitting the signal from the PTU operating in the slave node to the PRU with the operation of transmitting the signal from the PTU to the PRU so that the signal transmitted from the PTU operating in the slave mode does not interfere with the signal transmitted from the PTU.
The synchronizing may include synchronizing the operation of transmitting the signal from the PTU operating in the slave node to the PRU with the operation of transmitting the signal from the PTU to the PRU so that the PRU only receives one signal at a time.
The synchronizing may include transmitting a control signal to the PTU operating in the slave mode to control either one or both of a communication time or a communication frequency of the PTU operating in the slave mode.
Other features and aspects will be apparent from the following detailed description, the drawings, and the claims.
FIG. 1 illustrates an example of a wireless power transmission system.
FIGS. 2A and 2B illustrate examples of a distribution of a magnetic field in a resonator and a feeder.
FIGS. 3A and 3B illustrate an example of a configuration of a resonator and a feeder.
FIG. 4A illustrates an example of a distribution of a magnetic field inside a resonator produced by feeding a feeder.
FIG. 4B illustrates an example of equivalent circuits of a feeder and a resonator.
FIG. 5 illustrates an example of a method of synchronization control of a power transmitting unit (PTU).
FIGS. 6A and 6B illustrate examples of a network of PTUs.
FIGS. 7A through 7D illustrate examples of signal sequences of a master device and plurality of slave devices.
FIG. 8 illustrates an example of frequency hopping.
FIGS. 9A and 9B illustrate examples of a network-connection of a PTU.
FIG. 10 illustrates an example of a configuration of a PTU.
The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses, and/or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatuses, and/or systems described herein will be apparent to one of ordinary skill in the art. The sequences of operations described herein are merely examples, and not limited to those set forth herein, but may be changed as will be apparent to one of ordinary skill in the art, with the exception of operations necessarily occurring in a certain order. Also, description of functions and constructions that are well known to one of ordinary skill in the art may be omitted for increased clarity and conciseness.
Throughout the drawings and the detailed description, the same reference numerals refer to the same elements. The drawings may not be to scale, and the relative size, proportions, and depiction of elements in the drawings may be exaggerated for clarity, illustration, and convenience.
Communication schemes between a source and a target, or between a source and another source, may include an in-band communication scheme and an out-of-band communication scheme.
In the in-band communication scheme, the source and the target, or the source and the other source, communicate with each other using a frequency that is the same as a frequency used for power transmission.
In the out-of-band communication scheme, the source and the target, or the source and the other source. communicate with each other using a frequency that is different from a frequency used for power transmission.
FIG. 1 illustrates an example of a wireless power transmission system.
Referring to FIG. 1 , the wireless power transmission system includes a source 110 and a target 120 . The source 110 is a device configured to supply wireless power, and may include any electronic device capable of supplying power, for example, a pad, a terminal, a tablet personal computer (PC), a television (TV), a medical device, or an electric vehicle. The target 120 is a device configured to receive wireless power, and may include any electronic device requiring power to operate, for example, a pad, a terminal, a tablet PC, a medical device, an electric vehicle, a washing machine, a radio, or a lighting system.
The source 110 includes a variable switching mode power supply (SMPS) 111 , a power amplifier (PA) 112 , a matching network 113 , a transmission (Tx) controller 114 (for example, Tx control logic), a communicator 115 , and a power detector 116 .
The variable SMPS 111 generates a direct current (DC) voltage by switching an alternating current (AC) voltage having a frequency of tens of hertz (Hz) output from a power supply. The variable SMPS 111 may output a fixed DC voltage, or may output an adjustable DC voltage that may be adjusted under control of the Tx controller 114 .
The variable SMPS 111 may control its output voltage supplied to the PA 112 based on a level of power output from the PA 112 so that the PA 112 may operate in a saturation region with a high efficiency at all times, thereby enabling a maximum efficiency to be maintained at all levels of the output power of the PA 112 . The PA 112 may be, for example, a Class-E amplifier.
If a fixed SMPS is used instead of the variable SMPS 111 , a variable DC-to-DC (DC/DC) converter may be necessary. In this example, the fixed SMPS outputs a fixed DC voltage to the variable DC/DC converter, and the variable DC/DC converter controls its output voltage supplied to the PA 112 based on the level of the power output from the PA 112 so that the PA 112 , which may be a Class-E amplifier, may operate in the saturation region with a high efficiency at all times, thereby enabling the maximum efficiency to be maintained at all levels of the output power of the PA 112 .
The power detector 116 detects an output current and an output voltage of the variable SMPS 111 , and transmits, to the Tx controller 114 , information on the detected output current and the detected output voltage. Also, the power detector 116 may detect an input current and an input voltage of the PA 112 .
The PA 112 generates power by converting a DC voltage having a predetermined level supplied to the PA 112 by the variable SMPS 111 to an AC voltage using a switching pulse signal having a frequency in a band of a few megahertz (MHz) to tens of MHz. For example, the PA 112 may convert the DC voltage supplied to the PA 112 to an AC voltage having a reference resonant frequency F.sub.Ref, and may generate communication power used for communication, and/or charging power used for charging. The communication power and the charging power may be used in a plurality of targets.
If a high power from a few kilowatts (kW) to tens of kW is transmitted using a resonant frequency in a band of tens of kilohertz (kHz) to hundreds of kHz, the PA 112 may be omitted, and power may be supplied to a source resonator 131 from the variable SMPS 111 or a high-power power supply. For example, an inverter may be used in lieu of the PA 112 . The inverter may convert a DC power supplied from the high-power power supply to an AC power. The inverter may convert the power by converting a DC voltage having a predetermined level to an AC voltage using a switching pulse signal having a frequency in a band of tens of kHz to hundreds of kHz. For example, the inverter may convert the DC voltage having the predetermined level to an AC voltage having a resonant frequency of the source resonator 131 in a band of tens of kHz to hundreds of kHz.
As used herein, the term “communication power” refers to a low power of 0.1 milliwatt (mW) to 1 mW. The term “charging power” refers to a high power of a few mW to tens of kW consumed by a load of a target. As used herein, the term “charging” refers to supplying power to a unit or element configured to charge a battery or other rechargeable device. Additionally, the term “charging” refers to supplying power to a unit or element configured to consume power. For example, the term “charging power” may refer to power consumed by a target while operating, or power used to charge a battery of the target. The unit or element may be, for example, a battery, a display device, a sound output circuit, a main processor, or any of various types of sensors.
As used herein, the term “reference resonant frequency” refers to a resonant frequency nominally used by the source 110 , and the term “tracking frequency” refers to a resonant frequency used by the source 110 that has been adjusted based on a preset scheme.
The Tx controller 114 may detect a reflected wave of the communication power or the charging power, and may detect mismatching that occurs between a target resonator 133 and the source resonator 131 based on the detected reflected wave. To detect the mismatching, for example, the Tx controller 114 may detect an envelope of the reflected wave, a power amount of the reflected wave, or any other characteristic of the reflected wave that is affected by mismatching.
The matching network 113 compensates for impedance mismatching between the source resonator 131 and the target resonator 133 to achieve optimal matching under the control of the Tx controller 114 . The matching network 113 includes at least one inductor and at least one capacitor each connected to a respective switch controlled by the Tx controller 114 .
If a high power is to be transmitted using a resonant frequency in a band of tens of kHz to hundreds of kHz, the matching network 113 may be omitted from the source 110 because the effect of the matching network 113 may be reduced when transmitting the high power.
The Tx controller 114 may calculate a voltage standing wave ratio (VSWR) based on a level of an output voltage of the source resonator 131 or the PA 112 and a voltage level of the reflected wave. In one example, if the VSWR is greater than a predetermined value, the Tx controller 114 may determine that a mismatch is detected between the source resonator 131 and the target resonator 133 .
In another example, if the Tx controller 114 detects that the VSWR is greater than the predetermined value, the Tx controller 114 may calculate a wireless power transmission efficiency for each of N tracking frequencies, determine a tracking frequency F.sub.Best providing the best wireless power transmission efficiency among the N tracking frequencies, and adjust the reference resonant frequency F.sub.Ref to the tracking frequency F.sub.Best. The N tracking frequencies may be set in advance.
The Tx controller 114 may adjust a frequency of the switching pulse signal used by the PA 112 . The frequency of the switching pulse signal may be determined under the control of the Tx controller 114 . For example, by controlling the PA 112 , the Tx controller 114 may generate a modulated signal to be transmitted to the target 120 . In other words, the TX controller 114 may transmit a variety of data to the target 120 using in-band communication. The Tx controller 114 may also detect a reflected wave, and may demodulate a signal received from the target 120 from an envelope of the detected reflected wave.
The Tx controller 114 may generate a modulated signal for in-band communication using various methods. For example, the Tx controller 114 may generate the modulated signal by turning the switching pulse signal used by the PA 112 on and off, by performing delta-sigma modulation, or by any other modulation method known to one of ordinary skill in the art. Additionally, the Tx controller 114 may generate a pulse-width modulated (PWM) signal having a predetermined envelope.
The Tx controller 114 may determine an initial wireless power to be transmitted to the target 120 based on a change in a temperature of the source 110 , a battery state of the target 120 , a change in an amount of power received by the target 120 , and/or a change in a temperature of the target 120 .
The source 110 may further include a temperature measurement sensor (not illustrated) configured to detect a change in a temperature of the source 110 . The source 110 may receive from the target 120 information regarding the battery state of the target 120 , the change in the amount of power received by the target 120 , and/or the change in the temperature of the target 120 by communicating with the target 120 . The source 110 may detect the change in the temperature of the target 120 based on the information received from the target 120 .
The Tx controller 114 may adjust a voltage supplied to the PA 112 based on the change in the temperature of the target 120 using a lookup table (LUT). The LUT may store a level of the voltage to be supplied to the PA 112 based on the change in the temperature of the source 110 . For example, when the temperature of the source 110 rises, the Tx controller 114 may reduce the voltage to be supplied to the PA 112 by controlling the variable SMPS 111 .
The communicator 115 may perform out-of-band communication using a separate communication channel. The communicator 115 may include a communication module, such as a ZigBee module, a Bluetooth module, or any other communication module known to one of ordinary skill in the art, that the communicator 115 may use to transmit or receive data 140 to or from the target 120 using the out-of-band communication.
The source resonator 131 transmits electromagnetic energy 130 to the target resonator 133 . For example, the source resonator 131 may transmit the communication power or the charging power to the target 120 via magnetic coupling with the target resonator 133 .
The source resonator 131 may be made of a superconducting material. Also, although not shown in FIG. 1 , the source resonator 131 may be disposed in a container of coolant to enable the source resonator 131 to maintain a superconducting state. A heated coolant that has transitioned to a gaseous state may be liquefied to a liquid state by a cooler. The target resonator 133 may also be made of a superconducting material. In this instance, the target resonator 133 may also be disposed in a container of coolant to enable the target resonator 133 to maintain a superconducting state.
As illustrated in FIG. 1 , the target 120 includes a matching network 121 , a rectifier 122 , a DC/DC converter 123 , a communicator 124 , a reception (Rx) controller 125 (for example, Rx control logic), a voltage detector 126 , and a power detector 127 .
The target resonator 133 receives the electromagnetic energy 130 from the source resonator 131 . For example, the target resonator 133 may receive the communication power or the charging power from the source 110 via a magnetic coupling with the source resonator 131 . Additionally, the target resonator 133 may receive data from the source 110 using the in-band communication.
The target resonator 133 may receive the initial wireless power determined by the Tx controller 114 based on the change in the temperature of the source 110 , the battery state of the target 120 , the change in the amount of power received by the target 120 , and/or the change in the temperature of the target 120 .
The matching network 121 matches an input impedance viewed from the source 110 to an output impedance viewed from a load of the target 120 . The matching network 121 may be configured to have at least one capacitor and at least one inductor.
The rectifier 122 generates a DC voltage by rectifying an AC voltage received by the target resonator 133 .
The DC/DC converter 123 adjusts a level of the DC voltage output from the rectifier 122 based on a voltage required by the load. As an example, the DC/DC converter 123 may adjust the level of the DC voltage output from the rectifier 122 to a level in a range of 3 volts (V) to 10 V.
The voltage detector 126 detects a voltage of an input terminal of the DC/DC converter 123 , and the power detector 127 detects a current and a voltage of an output terminal of the DC/DC converter 123 . The detected voltage of the input terminal may be used to calculate a wireless power transmission efficiency of the power received from the source 110 . The detected current and the detected voltage of the output terminal may be used by the Rx controller 125 to calculate an amount of power actually transferred to the load. The Tx controller 114 of the source 110 may calculate an amount of power that needs to be transmitted by the source 110 to the target 120 based on an amount of power required by the load and the amount of power actually transferred to the load.
If the amount of the power actually transferred to the load calculated by the Rx controller 125 is transmitted to the source 110 by the communicator 124 , the Tx controller 114 may calculate the amount of power that needs to be transmitted to the target 120 , and may control either one or both of the variable SMPS 111 and the PA 112 to generate an amount of power that will enable the calculated amount of power to be transmitted by the source 110 .
The Rx controller 125 may perform in-band communication to transmit and receive data to and from the source 110 using a resonant frequency. During the in-band communication, the Rx controller 125 may demodulate a received signal by detecting a signal between the target resonator 133 and the rectifier 122 , or detecting an output signal of the rectifier 122 . In particular, the Rx controller 125 may demodulate a message received using the in-band communication.
Additionally, the Rx controller 125 may adjust an input impedance of the target resonator 133 using the matching network 121 to modulate a signal to be transmitted to the source 110 . For example, the Rx controller 125 may adjust the matching network 121 to increase the impedance of the target resonator 133 so that a reflected wave will be detected by the TX controller 114 of the source 110 . Depending on whether the reflected wave is detected, the Tx controller 114 of the source 110 may detect a first value, for example, a binary number “0,” or a second value, for example, a binary number “1.” For example, when the reflected wave is detected, the Tx controller 114 may detect “0”, and when the reflected wave is not detected, the Tx controller 114 may detect “1”. Alternatively, when the reflected wave is detected, the Tx controller 114 may detect “1”, and when the reflected wave is not detected, the Tx controller 114 may detect “0”.
The communicator 124 of the target 120 may transmit a response message to the communicator 115 of the source 110 . For example, the response message may include any one or any combination of a product type of the target 120 , manufacturer information of the target 120 , a model name of the target 120 , a battery type of the target 120 , a charging scheme of the target 120 , an impedance value of a load of the target 120 , information on characteristics of the target resonator 133 of the target 120 , information on a frequency band used by the target 120 , an amount of power consumed by the target 120 , an identifier (ID) of the target 120 , product version information of the target 120 , standard information of the target 120 , and any other information about the target 120 .
The communicator 124 may perform out-of-band communication using a separate communication channel. For example, the communicator 124 may include a communication module, such as a ZigBee module, a Bluetooth module, or any other communication module known to one of ordinary skill in the art, that the communicator 124 may use to transmit and receive the data 140 to and from the source 110 using the out-of-band communication.
The communicator 124 may receive a wake-up request message from the source 110 , and the power detector 127 may detect an amount of power received by the target resonator 133 . The communicator 124 may transmit to the source 110 information on the detected amount of the power received by the target resonator 133 . The information on the detected amount of the power received by the target resonator 133 may include, for example, an input voltage value and an input current value of the rectifier 122 , an output voltage value and an output current value of the rectifier 122 , an output voltage value and an output current value of the DC/DC converter 123 , and any other information about the detected amount of the power received by the target resonator 133 .
In the following description of FIGS. 2A through 4B , unless otherwise indicated, the term “resonator” may refer to both a source resonator and a target resonator. The resonator in FIGS. 2A through 4B may be used as the resonators described with respect to FIGS. 1 and 5-10 .
FIGS. 2A and 2B illustrate examples of a distribution of a magnetic field in a resonator and a feeder. When power is supplied to a resonator through a separate feeder, a magnetic field is generated in both the feeder and the resonator. A source resonator and a target resonator may each have a double loop structure including an external loop and an internal loop.
FIG. 2A is a diagram illustrating an example of a structure of a wireless power transmitter in which a feeder 210 and a resonator 220 do not have a common ground. Referring to FIG. 2A , when an input current flows into the feeder 210 through a terminal labeled “+” and out of the feeder 210 through a terminal labeled “−”, a magnetic field 230 is generated by the input current. A direction 231 of the magnetic field 230 inside the feeder 210 is into the plane of FIG. 2A , and is opposite to a direction 233 of the magnetic field 230 outside the feeder 210 , which is out of the plane of FIG. 2A . The magnetic field 230 generated in the feeder 210 induces a current to flow in the resonator 220 . A direction of the induced current in the resonator 220 is opposite to a direction of the input current in the feeder 210 as indicated by the dashed lines with arrowheads in FIG. 2A .
The induced current in the resonator 220 generates a magnetic field 240 . Directions of the magnetic field 240 generated by the resonator 220 are the same at all positions inside the resonator 220 , and are out of the plane of FIG. 2A . Accordingly, a direction 241 of the magnetic field 240 generated by the resonator 220 inside the feeder 210 is the same as a direction 243 of the magnetic field 240 generated by the resonator 220 outside the feeder 210 .
Consequently, when the magnetic field 240 generated by the feeder 210 and the magnetic field 240 generated by the resonator 220 are combined, a strength of the total magnetic field 240 decreases inside the feeder 210 , but increases outside the feeder 210 . Accordingly, when power is supplied to the resonator 220 via the feeder 210 configured as illustrated in FIG. 2 , the strength of the total magnetic field decreases in the portion of the resonator 220 inside the feeder 210 , but increases in the portion of the resonator 220 outside the feeder 210 . When a distribution of a magnetic field is random or not uniform in the resonator 220 , it may be difficult to perform impedance matching because an input impedance may frequently vary. Additionally, when the strength of the total magnetic field increases, a wireless power transmission efficiency increases. Conversely, when the strength of the total magnetic field decreases, the wireless power transmission efficiency decreases. Accordingly, the wireless power transmission efficiency may be reduced on average.
FIG. 2B illustrates an example of a structure of a wireless power transmitter in which a resonator 250 and a feeder 260 have a common ground. The resonator 250 includes a capacitor 251 . The feeder 260 receives a radio frequency (RF) signal via a port 261 . When the RF signal is input to the feeder 260 , an input current is generated in the feeder 260 . The input current flowing in the feeder 260 generates a magnetic field, and a current is induced in the resonator 250 by the magnetic field. Also, another magnetic field is generated by the induced current flowing in the resonator 250 . In this example, a direction of the input current flowing in the feeder 260 is opposite to a direction of the induced current flowing in the resonator 250 . Accordingly, in a region between the resonator 250 and the feeder 260 , a direction 271 of the magnetic field generated by the input current is the same as a direction 273 of the magnetic field generated by the induced current, and thus the strength of the total magnetic field increases. Conversely, inside the feeder 260 , a direction 281 of the magnetic field generated by the input current is opposite to a direction 283 generated by the induced current, and thus the strength of the total magnetic field decreases. Therefore, the strength of the total magnetic field decreases in a portion of the resonator 250 inside the feeder 260 , but increases in a portion of the resonator 250 outside the feeder 260 .
An input impedance may be adjusted by adjusting an internal area of the feeder 260 . The input impedance is an impedance viewed in a direction from the feeder 260 to the resonator 250 . When the internal area of the feeder 260 increases, the input impedance increases, and when the internal area of the feeder 260 decreases, the input impedance decreases. However, if the magnetic field is randomly or not uniformly distributed in the resonator 250 , the input impedance value may vary based on a location of a target even if the internal area of the feeder 260 has been adjusted to adjust the input impedance to match an output impedance of a power amplifier for a specific location of the target device. Accordingly, a separate matching network may be needed to match the input impedance to the output impedance of the power amplifier. For example, when the input impedance increases, a separate matching network may be needed to match the increased input impedance to a relatively low output impedance of the power amplifier.
FIGS. 3A and 3B illustrate an example of a configuration of a resonator and a feeder.
Referring to FIG. 3A , a resonator 310 includes a capacitor 311 . A feeder 320 is electrically connected to both ends of the capacitor 311 .
FIG. 3B illustrates a structure of FIG. 3A in greater detail. The resonator 310 includes a first transmission line (not identified by a reference numeral in FIG. 3B , but formed by various elements in FIG. 3B as discussed below), a first conductor 341 , a second conductor 342 , and at least one capacitor 350 .
The capacitor 350 is connected in series between a first signal conducting portion 331 and a second signal conducting portion 332 in the first transmission line, causing an electric field to be concentrated in the capacitor 350 . In general, a transmission line includes at least one conductor disposed in an upper portion of the transmission line, and at least one conductor disposed in a lower portion of the transmission line. A current may flow through the at least one conductor disposed in the upper portion of the transmission line, and the at least one conductor in the lower portion of the transmission line may be electrically grounded. In the example in FIG. 3B , a conductor disposed in the upper portion of the first transmission line is separated into two portions that will be referred to as the first signal conducting portion 331 and the second signal conducting portion 332 , and a conductor disposed in the lower portion of the first transmission line will be referred to as a first ground conducting portion 333 .
As shown in FIG. 3B , the resonator has a generally two-dimensional (2D) structure. The first transmission line includes the first signal conducting portion 331 and the second signal conducting portion 332 in the upper portion of the first transmission line, and the first ground conducting portion 333 in the lower portion of the first transmission line. The first signal conducting portion 331 and the second signal conductor portion are disposed to face the first ground conducting portion 333 . A current flows through the first signal conducting portion 333 and the second signal conducting portion 332 .
Also, as shown in FIG. 3B , one end of the first signal conducting portion 331 is connected to one end of the first conductor 341 , the other end of the first signal conducting portion 331 is connected to one end of the capacitor 350 , and the other end of the first conductor 341 is connected to one end of the first ground conducting portion 333 . One end of the second signal conducting portion 332 is connected to one end of the second conductor 342 , the other end of the second signal conducting portion 332 is connected to the other end of the capacitor 350 , and the other end of the second conductor 342 is connected to the other end of the first ground conducting portion 333 . Accordingly, the first signal conducting portion 331 , the second signal conducting portion 332 , the first ground conducting portion 333 , the first conductor 341 , and the second conductor 342 are connected to one another, causing the resonator 310 to have an electrically closed loop structure. The term “loop structure” includes a polygonal structure, a circular structure, a rectangular structure, and any other geometrical structure that is closed, i.e., a geometrical structure that does not have any opening in its perimeter. The expression “having a loop structure” indicates a structure that is electrically closed.
The capacitor 350 is inserted into an intermediate portion of the first transmission line. In the example in FIG. 3B , the capacitor 350 is inserted into a space between the first signal conducting portion 331 and the second signal conducting portion 332 . The capacitor 350 may be a lumped element capacitor, a distributed element capacitor, or any other type of capacitor known to one of ordinary skill in the art. For example, a distributed element capacitor may include zigzagged conductor lines and a dielectric having a high permittivity disposed between the zigzagged conductor lines.
The capacitor 350 inserted into the first transmission line may cause the resonator 310 to have a characteristic of a metamaterial. A metamaterial is a material having an electrical characteristic that is not found in nature, and thus may have an artificially designed structure. All materials existing in nature have a permittivity and a magnetic permeability. Most materials have a positive permittivity and a positive magnetic permeability.
In the case of most materials, a right-hand rule may be applied to an electric field, a magnetic field, and a Poynting vector, so the corresponding materials may be referred to as right-handed materials (RHMs). However, a metamaterial having a permittivity and/or a magnetic permeability not found in nature may be classified into an epsilon negative (ENG) material, a mu negative (MNG) material, a double negative (DNG) material, a negative refractive index (NRI) material, a left-handed (LH) material, and any other metamaterial classification known to one of ordinary skill in the art based on a sign of the permittivity of the metamaterial and a sign of the magnetic permeability of the metamaterial.
If the capacitor 350 is a lumped element capacitor and a capacitance of the capacitor 350 is appropriately determined, the resonator 310 may have a characteristic of a metamaterial. If the resonator 310 is caused to have a negative magnetic permeability by appropriately adjusting the capacitance of the capacitor 350 , the resonator 310 may also be referred to as an MNG resonator. Various criteria may be applied to determine the capacitance of the capacitor 350 . For example, the various criteria may include a criterion for enabling the resonator 310 to have the characteristic of the metamaterial, a criterion for enabling the resonator 310 to have a negative magnetic permeability at a target frequency, a criterion for enabling the resonator 310 to have a zeroth-order resonance characteristic at the target frequency, and any other suitable criterion. Based on any one or any combination of the aforementioned criteria, the capacitance of the capacitor 350 may be appropriately determined.
The resonator 310 , hereinafter referred to as the MNG resonator 310 , may have a zeroth-order resonance characteristic of having a resonant frequency when a propagation constant is “0”. When the MNG resonator 310 has the zeroth-order resonance characteristic, the resonant frequency is independent of a physical size of the MNG resonator 310 . The resonant frequency of the MNG resonator 310 having the zeroth-order resonance characteristic may be changed without changing the physical size of the MNG resonator 310 by changing the capacitance of the capacitor 350 .
In a near field, the electric field is concentrated in the capacitor 350 inserted into the first transmission line, causing the magnetic field to become dominant in the near field. The MNG resonator has a relatively high Q-factor when the capacitor 350 is a lumped element capacitor, thereby increasing a wireless power transmission efficiency. The Q-factor indicates a level of an ohmic loss or a ratio of a reactance with respect to a resistance in the wireless power transmission. As will be understood by one of ordinary skill in the art, the wireless power transmission efficiency will increase as the Q-factor increases.
Although not illustrated in FIG. 3B , a magnetic core passing through the MNG resonator 310 may be provided to increase a wireless power transmission distance.
Referring to FIG. 3B , the feeder 320 includes a second transmission line (not identified by a reference numeral in FIG. 3B , but formed by various elements in FIG. 3B as discussed below), a third conductor 371 , a fourth conductor 372 , a fifth conductor 381 , and a sixth conductor 382 .
The second transmission line includes a third signal conducting portion 361 and a fourth signal conducting portion 362 in an upper portion of the second transmission line, and a second ground conducting portion 363 in a lower portion of the second transmission line. The third signal conducting portion 361 and the fourth signal conducting portion 362 are disposed to face the second ground conducting portion 363 . A current flows through the third signal conducting portion 361 and the fourth signal conducting portion 362 .
The description continues in the full USPTO document.
About 6,845 words. The USPTO PDF has it with every drawing.
Fees are due 3.5, 7.5 and 11.5 years after grant. This patent expired on February 27, 2026, so the fee marked "not paid" was the one that went unpaid.
METHOD AND APPARATUS FOR SYNCHRONIZATION CONTROL IN WIRELESS POWER TRANSMISSION SYSTEM
Filed Jul 2014 · published Jan 2015Method and apparatus for synchronization control in wireless power transmission system
Filed Jul 2014 · granted Feb 2018Earlier publications, parents and continuations. None of them can still be enforced, or this patent would not be listed.
Prior art cited by the examiner or applicant. Useful when you check your own idea for novelty.
Everything on this page comes from the documents linked above.
